Can you hit behind the head if opponent bent over?

[ross]

Is it not illegal to crouch below your opponents waistline ?
Floyd managed to hit Hatton on the back of his head I remember and didnt get warned, Hattons head was outside the ropes at the time tho.

Found it:
You can't hold your opponent and hit him at the same time, or duck so low that your head is below your opponent's belt line
Rules of Boxing - Boxrec Boxing Encyclopaedia

Floyd should of been DQ'ed against Hatton then, but it was Cortez and he dont know shit !

Yep, if one fighter breaks the rules and the opponent has only broken the rules because of it, then the opponents rule flouting doesnt really count. Like a fighter turning his back outside of a break or ducking below the belt line. Its not the opponents fault but it is the refs fault for allowing it to happen.